1. Field of the Invention
The present invention relates to an air conditioner that can reduce power consumption of an outdoor device in a standby state.
2. Description of the Related Art
Configurations of air conditioners for reducing the power consumption of the outdoor device in a standby state has been previously proposed, for example, in Japanese Patent Application Laid-open No. 2010-243051.
In the air conditioner described in Japanese Patent Application Laid-open No. 2010-243051, an indoor device and an outdoor device are connected to each other with a three-core cable that includes a power line, a common line, and a signal line, and a commercial power source is connected to either one of the outdoor device and the indoor device so that power is supplied via the power line and the common line. The indoor device includes an outdoor activation relay that opens and closes the connection between the power line and the signal line, and an indoor control unit that operates the outdoor activation relay so that the commercial power is supplied between the signal line and the common line. The outdoor device includes a power supply relay that opens and closes a connection between the commercial power source and an outdoor rectifier circuit, and closes the power supply relay when commercial power is supplied between the signal line and the common line.
With an air conditioner that operates with an external power supply, the bus voltage inevitably drops when the power supply is cut during energization. In a configuration in which the power supply relay remains closed when the external power supply is cut during energization, an inrush current generated when the power supply is restarted may cause a failure in the power supply relay and the rectifier circuit. Therefore, it is necessary to select a power supply relay and a rectifier circuit element that can withstand the inrush current in a conventional air conditioner.
Further, it is also possible that the power supply relay is kept open when the external power supply is cut in order to prevent the failure of the power supply relay and the rectifier circuit element. However, with such a control technique, self-recovery cannot be achieved even after the power supply is restarted. To restart the operation of the outdoor device in this case, after the outdoor device is turned off, it is necessary to supply commercial power between the signal line and the common line in the indoor device in order to supply power to the outdoor device anew. Therefore, even when there is an instantaneous power failure that lasts for a short while, there is still a problem in that it is necessary to reactivate the outdoor device, thus making the stop time longer and the operation less user friendly.